Astrocytes are intimately involved in the formation and development of retinal vessels. Astrocyte dysfunction is a major cause of blood-retinal barrier injury and other retinal vascular diseases. In this study, the de...Astrocytes are intimately involved in the formation and development of retinal vessels. Astrocyte dysfunction is a major cause of blood-retinal barrier injury and other retinal vascular diseases. In this study, the development of the retinal vascular system and the formation of the blood-ret-inal barrier in mice were investigated using immunolfuorescence staining, gelatin-ink perfusion, and transmission electron microscopy. The results showed that the retinal vascular system of mice develops from the optic disc after birth, and radiates out gradually to cover the entire retina, taking the papilla optica as the center. First, the superifcial vasculature is formed on the inner retinal layer;then, the vasculature extends into the inner and outer edges of the retinal inner nuclear layer, forming the deep vasculature that is parallel to the superifcial vasculature. The blood-retinal barrier is mainly composed of endothelium, basal lamina and the end-feet of astrocytes, which become mature during mouse development. Initially, the naive endothelial cells were immature with few organelles and many microvilli. The basal lamina was uniform in thickness, and the glial end-feet surrounded the outer basal lamina incompletely. In the end, the blood-retinal barrier matures with smooth endothelia connected through tight junctions, rela-tively thin and even basal lamina, and relatively thin glial cell end-feet. These ifndings indicate that the development of the vasculature in the retina follows the rules of“center to periphery”and“superifcial layer to deep layers”. Its development and maturation are spatially and tempo-rally consistent with the functional performance of retinal neurons and photosensitivity. The blood-retinal barrier gradually becomes mature via the process of interactions between astro-cytes and blood vessel cells.展开更多
Design and optimization of electrical drive systems often involve simultaneous consideration of multiple objectives that usually contradict to each other and multiple disciplines that normally coupled to each other.Th...Design and optimization of electrical drive systems often involve simultaneous consideration of multiple objectives that usually contradict to each other and multiple disciplines that normally coupled to each other.This paper aims to present efficient system-level multiobjective optimization methods for the multidisciplinary design optimization of electrical drive systems.From the perspective of quality control,deterministic and robust approaches will be investigated for the development of the optimization models for the proposed methods.Meanwhile,two approximation methods,Kriging model and Taylor expansion are employed to decrease the computation/simulation cost.To illustrate the advantages of the proposed methods,a drive system with a permanent magnet synchronous motor driven by a field oriented control system is investigated.Deterministic and robust Pareto optimal solutions are presented and compared in terms of several steady-state and dynamic performances(like average torque and speed overshoot)of the drive system.The robust multiobjective optimization method can produce optimal Pareto solutions with high manufacturing quality for the drive system.展开更多
We have developed a new form of intravascular optical coherence tomography(IV-OCT) that allows the extremely fast acquisition of high-resolution images of the coronary arteries.This process leads to much better image ...We have developed a new form of intravascular optical coherence tomography(IV-OCT) that allows the extremely fast acquisition of high-resolution images of the coronary arteries.This process leads to much better image quality by eliminating cardiac motion artefacts and undersampling.It relies on a catheter that incorporates a synchronous micromotor with a diameter of 1.0 mm and a rotational speed of up to5600 revolutions per second,enabling an IV-OCT frame rate of 5.6 kHz.This speed is matched by a wavelength-swept laser that generates up to 2.8 million image lines per second.With this setup,our team achieved IV-OCT imaging of up to5600 frames per second(fps) in vitro and 4000 fps in vivo,deployed at a 100 mm·s^(-1) pullback velocity.The imaging session is triggered by the electrocardiogram of the subject,and can scan a coronary artery in the phase of the heartbeat where the heart is at rest,providing a name for this new technology:the "Heartbeat OCT."展开更多
Zn is a frequently used and sometimes even an inevitably involved element (when zeolitic imidazolate framework-8 (ZIF-8) is adopted as the precursor) for preparing high-performance Fe-N-C oxygen reduction reaction (OR...Zn is a frequently used and sometimes even an inevitably involved element (when zeolitic imidazolate framework-8 (ZIF-8) is adopted as the precursor) for preparing high-performance Fe-N-C oxygen reduction reaction (ORR) catalysts. However, how the Zn element affects the physicochemical architecture of the catalysts, how it enhances the catalytic activity and whether Zn atoms serve as the active centers remain unclear. Herein, we proposed a novel route that adopted pyrrole as the precursor and flexibly controlled the addition of exogenous Zn and Fe dopants before pyrrole polymerization. In this way, a series of nitrogen-carbon catalysts with or without Zn or Fe doping were synthesized. The detailed characterization revealed the role of Zn and Fe doping in the catalyst morphology, pore structure, active site configurations, ORR catalytic activity and fuel cell performance. Importantly, the findings revealed that Zn doping has little effect on the ORR mechanism and pathway. It enhances ORR activity primarily by increasing the number of active sites via introducing more micro- and meso-pores, rather than by creating new active sites. While Fe doping participated in forming both pores and active site centers. Moreover, the catalyst that co-doped with Zn and Fe atoms (Zn-FeNC), synthesized via this simple and template-free route we proposed, presented a unique hollow and hierarchical pore structure with highly boosted ORR activity. It exhibited a 40 mV higher E 1/2 value than Pt/C in alkaline media, along with a rapid current response in air-cathode of the direct formate fuel cell. These results are valuable in guiding the synthesis of high-performance Fe-N-C catalysts.展开更多
One major function of adipocytes is to store excess energy in the form of triglycerides. Insufficient adipose lipid storage is asso- ciated with many pathological conditions including hyperlipidemia, insulin resistanc...One major function of adipocytes is to store excess energy in the form of triglycerides. Insufficient adipose lipid storage is asso- ciated with many pathological conditions including hyperlipidemia, insulin resistance, and type 2 diabetes. In this study, we observed the overexpression of SUMO-specific protease 2 （Senp2） in adipose tissues during obesity. Adipocyte 5enp2 deficiency resulted in less adipose lipid storage accompanied by an ectopic fat accumulation and insulin resistance under high-fat diet feeding. We further found that SET domain bifurcated 1 （Setdbl） was a SUMOylated protein and that SUMOylation promoted Setdbl occupancy on the promoter locus of Pparg and Cebpa genes to suppress their expressions by H3Kgme3. Senp2 could suppress Setdbl function by de-SUMOylation. In adipocyte 5enp2-deficiency mice, accumulation of the SUMOylated Setdbl suppressed the expression of Pparg and Cebpo genes as welt as lipid metabolism-related target genes, which would decrease the ability of lipid storage in adipocytes. These results revealed the crucial role of Senp2-Setdbl axis in controlling adipose lipid storage.展开更多
基金supported by the National Natural Science Foundation of China,No.30771140,31070952 and U1204311
文摘Astrocytes are intimately involved in the formation and development of retinal vessels. Astrocyte dysfunction is a major cause of blood-retinal barrier injury and other retinal vascular diseases. In this study, the development of the retinal vascular system and the formation of the blood-ret-inal barrier in mice were investigated using immunolfuorescence staining, gelatin-ink perfusion, and transmission electron microscopy. The results showed that the retinal vascular system of mice develops from the optic disc after birth, and radiates out gradually to cover the entire retina, taking the papilla optica as the center. First, the superifcial vasculature is formed on the inner retinal layer;then, the vasculature extends into the inner and outer edges of the retinal inner nuclear layer, forming the deep vasculature that is parallel to the superifcial vasculature. The blood-retinal barrier is mainly composed of endothelium, basal lamina and the end-feet of astrocytes, which become mature during mouse development. Initially, the naive endothelial cells were immature with few organelles and many microvilli. The basal lamina was uniform in thickness, and the glial end-feet surrounded the outer basal lamina incompletely. In the end, the blood-retinal barrier matures with smooth endothelia connected through tight junctions, rela-tively thin and even basal lamina, and relatively thin glial cell end-feet. These ifndings indicate that the development of the vasculature in the retina follows the rules of“center to periphery”and“superifcial layer to deep layers”. Its development and maturation are spatially and tempo-rally consistent with the functional performance of retinal neurons and photosensitivity. The blood-retinal barrier gradually becomes mature via the process of interactions between astro-cytes and blood vessel cells.
文摘Design and optimization of electrical drive systems often involve simultaneous consideration of multiple objectives that usually contradict to each other and multiple disciplines that normally coupled to each other.This paper aims to present efficient system-level multiobjective optimization methods for the multidisciplinary design optimization of electrical drive systems.From the perspective of quality control,deterministic and robust approaches will be investigated for the development of the optimization models for the proposed methods.Meanwhile,two approximation methods,Kriging model and Taylor expansion are employed to decrease the computation/simulation cost.To illustrate the advantages of the proposed methods,a drive system with a permanent magnet synchronous motor driven by a field oriented control system is investigated.Deterministic and robust Pareto optimal solutions are presented and compared in terms of several steady-state and dynamic performances(like average torque and speed overshoot)of the drive system.The robust multiobjective optimization method can produce optimal Pareto solutions with high manufacturing quality for the drive system.
文摘We have developed a new form of intravascular optical coherence tomography(IV-OCT) that allows the extremely fast acquisition of high-resolution images of the coronary arteries.This process leads to much better image quality by eliminating cardiac motion artefacts and undersampling.It relies on a catheter that incorporates a synchronous micromotor with a diameter of 1.0 mm and a rotational speed of up to5600 revolutions per second,enabling an IV-OCT frame rate of 5.6 kHz.This speed is matched by a wavelength-swept laser that generates up to 2.8 million image lines per second.With this setup,our team achieved IV-OCT imaging of up to5600 frames per second(fps) in vitro and 4000 fps in vivo,deployed at a 100 mm·s^(-1) pullback velocity.The imaging session is triggered by the electrocardiogram of the subject,and can scan a coronary artery in the phase of the heartbeat where the heart is at rest,providing a name for this new technology:the "Heartbeat OCT."
基金supported by the National Natural Science Foundation of China(No.52306248)Natural Science Foundations of Hunan Province of China(Nos.2024JJ6387 and 2024JJ6370)+1 种基金Scientific Research Foundation of the University of South China(Nos.230XQD020 and 230XQD021)Natural Science Foundation of Chongqing of China(No.CSTB2023NSCQ-MSX0926).
文摘Zn is a frequently used and sometimes even an inevitably involved element (when zeolitic imidazolate framework-8 (ZIF-8) is adopted as the precursor) for preparing high-performance Fe-N-C oxygen reduction reaction (ORR) catalysts. However, how the Zn element affects the physicochemical architecture of the catalysts, how it enhances the catalytic activity and whether Zn atoms serve as the active centers remain unclear. Herein, we proposed a novel route that adopted pyrrole as the precursor and flexibly controlled the addition of exogenous Zn and Fe dopants before pyrrole polymerization. In this way, a series of nitrogen-carbon catalysts with or without Zn or Fe doping were synthesized. The detailed characterization revealed the role of Zn and Fe doping in the catalyst morphology, pore structure, active site configurations, ORR catalytic activity and fuel cell performance. Importantly, the findings revealed that Zn doping has little effect on the ORR mechanism and pathway. It enhances ORR activity primarily by increasing the number of active sites via introducing more micro- and meso-pores, rather than by creating new active sites. While Fe doping participated in forming both pores and active site centers. Moreover, the catalyst that co-doped with Zn and Fe atoms (Zn-FeNC), synthesized via this simple and template-free route we proposed, presented a unique hollow and hierarchical pore structure with highly boosted ORR activity. It exhibited a 40 mV higher E 1/2 value than Pt/C in alkaline media, along with a rapid current response in air-cathode of the direct formate fuel cell. These results are valuable in guiding the synthesis of high-performance Fe-N-C catalysts.
基金This work was supported by grants from the National Natural Science Foundation of China （91019021 and 81430069 to J.C.）, the National Basic Research Program of China （973 Program） （2013CB910902 to J.C.）, Shanghai Committee of Science and Technology （15ZR1424500 to T.W. and 15140904300）, Shanghai Municipal Education Commission （ZZjdyx15003 to T.W. and 2017-01-07-00-01-E00050 to J.C.）, and Shanghai Jiao Tong University School of Medicine （14XJ10001 to T.W.）.
文摘One major function of adipocytes is to store excess energy in the form of triglycerides. Insufficient adipose lipid storage is asso- ciated with many pathological conditions including hyperlipidemia, insulin resistance, and type 2 diabetes. In this study, we observed the overexpression of SUMO-specific protease 2 （Senp2） in adipose tissues during obesity. Adipocyte 5enp2 deficiency resulted in less adipose lipid storage accompanied by an ectopic fat accumulation and insulin resistance under high-fat diet feeding. We further found that SET domain bifurcated 1 （Setdbl） was a SUMOylated protein and that SUMOylation promoted Setdbl occupancy on the promoter locus of Pparg and Cebpa genes to suppress their expressions by H3Kgme3. Senp2 could suppress Setdbl function by de-SUMOylation. In adipocyte 5enp2-deficiency mice, accumulation of the SUMOylated Setdbl suppressed the expression of Pparg and Cebpo genes as welt as lipid metabolism-related target genes, which would decrease the ability of lipid storage in adipocytes. These results revealed the crucial role of Senp2-Setdbl axis in controlling adipose lipid storage.
